Conventional door and window security systems may utilize a magnet and magnetometer to provide an indication of whether an entry point is open or closed. This binary result may be utilized by a home security system to determine whether it can be placed in an “away” mode or a “home” mode. An “away” mode for the home security system may be utilized, for example, when the occupants are away. In the away mode, the entry points into a home may be monitored for intrusion by an unwanted party. A “home” mode may refer to the home security system's state when the occupants are home. The mode can affect the actions taken by the security system in response to sensed activities in the home. For example, in home mode, the sensed opening of an exterior door may result in no action being taken by the security system. In the away mode, the sensed opening of the same door may be construed as an intrusion detection and may trigger a call to the police. There can also be an intermediate mode between stay and away. For example, there can be a “night” mode for when occupants are sleeping in the home. This mode can, for example, refrain from triggering an alert to the police based on sensed movement in the bedroom and hallways, but send such an alert when an exterior door is opened. The system can transition between modes when a user enters a security code into an entryway security system. Such modes apply to the security system for the whole home.
A home security system that has a home and/or an away state, however, may not detect nuances in usage of entry points and desired security features. For example, if the system determines that a door is open, the security system may not allow an occupant to place the system into an away mode. The system may notify the occupant that it cannot be placed in the away mode because an entry point is open. As an example, an occupant may desire to leave a door or window slightly ajar or open to allow fresh air into the home. To circumvent the home security system, the occupant may place a second magnet in a position that can be detected by the magnetometer when the door or window is open. Thus, the magnetometer may be tricked into thinking that the door or window is closed because it detects the presence of the magnetic field emitted by the magnet. Consequently, the home security system may be placed into an away mode. The placement of a second magnet can also be utilized by an intruder to trick the home security system.
Some other examples of security systems for entry points employing a magnetometer and a magnet include government and bank installations. These examples tend to utilize extremely complex security systems that may utilize balanced read switches that require a specific magnetic field in order to trigger a sensor. The installation of such security systems is very complex, often requiring a multimeter to be connected to the magnetometer to ensure that the sensor is placed in the correct spot.